Polysomnography (PSG)


A PSG is an overnight test to monitor how your brain and body functions while you sleep to help diagnose sleep disorders

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What is a PSG sleep study?

If you're experiencing problems with your sleeping habits, including chronic insomnia, daytime sleepiness, sleep walking or sleep-related breathing difficulties, your consultant might recommend an overnight sleep study. The main test used to analyse your brain and body as you sleep is a PSG.

Need to know

You'll arrive at the hospital on the evening of your scheduled sleep study. A porter will welcome you and show you to your private en-suite bedroom. Your consultant will attach a number of sensors to your head, chest and legs using small sticky pads or bands to hold them in place.

These painless sensors monitor important bodily functions while you sleep, including brain waves, eye movement, heart rate and muscle activity. You'll also have a clip on your finger to measure your oxygen levels and a sensor to measure your breathing. You'll be monitored throughout the night via video. Despite all the sensors, most people are still able to sleep.

Your consultant will explain the test to you and answer any questions you may have. They'll talk to you about your sleeping patterns and any problems or symptoms you're experiencing. They'll let you know how to prepare for your hospital stay and if there is anything specific you need to do before the test. This may include avoiding certain medications, caffeine, smoking or alcohol. You may also be asked to keep a sleep diary in the days or weeks leading up to your test.

After your test your consultant will remove the sensors and let you know about any next steps. If you're not staying for further diagnostic tests, you should be able to return home that morning.

Your consultant will review the video alongside the other measurements taken throughout the night to help diagnose a potential sleep disorder. The video is particularly important if you experience seizures or nocturnal epilepsy. You'll come back for a follow-up appointment to review your results and discuss options for treatment or further assessments if needed.

Our locations

London Bridge Hospital

London Bridge Hospital

27 Tooley Street SE1 2PR London

This content is intended for general information only and does not replace the need for personal advice from a qualified health professional.